Lab Flashcards
What tests do we do in the Lab?
Thickening Time HPHT Ultrasonic Cement Analyzer (UCA) Rheology Free Fluid Fluid Loss Gel Strength Slurry Settling Crush Test
Free Fluid
ability to prevent fluid separation. The problems this can cause are water loss, channeling, gas migration. 1.4% is the maximum allowed by Halliburton standard.
Otherwise channeling can ocurr and settling
Fluid Loss
Test the ability to retain water in the slurry. Nitrogen is pumped into a slurry sitting on a 325 mesh screen. Volume and time for the nitrogen to make its way through is calculated into formula. Bad fluid loss tests can change the densities, volumes and cause bridging, Fluid loss is one of the worst things to have. reduces compressive strength, and is really bad to have during a squeeze job.
Tested at 1000 psi for 30 minutes or until machine sputters
Rheology Test
Conditioned for 30 minutes in atmospheric consistometer
Visometer- Tests for slurry’s plastic viscosity at different sheer stress levels. It also tests for frictional properties and yield points. Readings are taken at various speeds to help determine necessary pump rate for turbulent flow, max pump rate, horsepower, frictional pressures, and time
Sonic Strength Test
UCA analyzer tests estimated compressive strength at different times in the hydration process. Records time to reach 50 psi and 500 psi. Heated to BHCT then to BHST slowly for desired test time
Thickening Time Test
Done using the High Pressure High Temperature consistometer. Uses temperature, pressure and time to determine when the slurry is no longer
Pumpable at 70bc.
API 100 Bc
No longer mixable @ 50bc
Compressabilty Test
Certain additives like Gas Stop and Super CBL liberate Gas from the slurry. The reaction should happen before the cement goes static. This test measures the time that reaction will happen.
Static Gel Strength
Two Tests. Zero Gel Time and Transition time. Zero Gel time is when the slurry reaches 100 lb/ 100ft2. The Transition time is the time it takes from zero gel time to 500lb. Once this number is hit, the slurry no longer transmits hydrostatic on the rest of the slurry.
Settling Test
Sees if the slurry experiences particle sedimentation. Determines the static stability of the slurry.
Potentiometer
Caliberated spring that shows consistency based on the thickening of slurry @ temp and Pressure
Thickening Time
Time it takes from mixing to reach 70bc based off of BHCT
Transition Time
Time for slurry in gel strength to go from 100lb/100sqft to 500lb/100sqft, Measured using Macs Analyzer
